Dear Editor,
Following our recent management of an adult patient with stridor, we performed a systematic review of published case reports and case series of adult patients presenting to the emergency department with stridor. The aim of our search was to outline the underlying causes of stridor in adults and we present our findings below. Our experience also emphasises the need for immediate management using a multi-disciplinary approach.
We performed a PubMed literature search from January 1951 to September 2014 using the following medical subject heading terms: ‘stridor’ OR ‘stridorous’ OR ‘stridors’ [Title], in English.
Stridor was reported in 249 patients from 99 publications (87 were single-patient case reports). We excluded reports on children and hospital acquired stridors (as a complication of tracheal intubation/general anaesthesia, thyroidectomy, pneumonectomy, nerve injury or other) as their management follows different pathways.
Malignant obstruction was reported in 15 patients. Fifty six percent of the reported patients were female. Approximately 50% of patients required definitive airway management, invasive ventilation and admission to the intensive care unit (ICU). The overall mortality rate was 6.4%. The identified aetiologies of the cases are summarised in Table 1.
Table 1.
Causes of stridor in adults presenting from the community as identified from a review of published case reports and case series.
| Causes of stridor in adults | No. of patients | No. of reports |
|---|---|---|
| Primary airway lesions | 17 | 15 |
| Autoimmune | 18 | 12 |
| Oesophageal | 18 | 16 |
| Vocal cord diseases | 27 | 10 |
| Infectious, inflammatory, immunodeficiency, idiopathic | 9 | 7 |
| Neurological | 65 | 13 |
| Thyroid and parathyroid disease (excluding post surgery) | 14 | 14 |
| Thoracic aortic aneurysm | 4 | 3 |
| Metabolica | 4 | 4 |
| Psychogenic | 53 | 3 |
| Exercise in elite athletes | 19 | 1 |
| Osteophytes | 1 | 1 |
| Total | 249 | 99 |
Two patients with hypokalaemia and two patients with hypocalcaemia as the primary metabolic disturbances.
The commonest systemic cause of stridor was neurological (65 patients from 13 papers). The commonest neurological cause was multiple system atrophy (53 patients) followed by myasthenia gravis (five patients).
The commonest local causes were vocal cord conditions (27 patients from 10 papers). Fifty-three patients from three reports had psychogenic stridor, a diagnosis of exclusion.1,2
The number of reported local causes for stridor was 59 versus 40 systemic causes. Subgroup analysis of obscure laryngeal causes of stridor revealed: redundant aryepiglottic fold (seven patients), focal dystonia (six patients), functional dyskinesia (six patients), paradoxical motion (five patients), laryngocele (one patient), subglottic stenosis (one patient) and tracheomalacia (one patient).
Regardless of cause, stridor implies critical airway obstruction of at least 50% of the airway lumen.3,4 Patients with stridor are at high risk of respiratory failure and death and require initial stabilisation to maintain ventilation and oxygenation, if this is consistent with the goals of care.3–5 The degree of respiratory distress depends on whether partial airway obstruction has developed gradually (e.g. laryngeal tumour) or rapidly (e.g. acute epiglottitis). Unless resolved promptly in the emergency department, patients require transfer to the ICU or operating theatres. Emergent steps to secure an airway should precede any other intervention. The main airway management options are
Tracheostomy under local anaesthesia and
Inhalational induction of anaesthesia and tracheal intubation (or tracheostomy under general anaesthesia if anatomy is difficult to visualise and while the patient still maintains adequate spontaneous ventilation).3–5 Awake fibreoptic intubation is not a necessarily the safest technique for patients with advanced upper airway obstruction due to difficulty in achieving good local anaesthesia in the presence of a tumour or inflammation, the risk of haemorrhage (particularly with supraglottic lesions), the risk of ‘corking off’ the patient’s remaining airway and the poor view in very narrow orifices.3–6 A fall-back position should be rehearsed and the procedure should be undertaken in the operating theatre by a senior anaesthetist with a senior surgeon scrubbed and with a tracheostomy set open.
Stridor is an important clinical sign associated with a variety of causes. The outcome depends on immediate appreciation that it is a sign of a life-threatening airway emergency, prompt treatment of reversible causes and an early multidisciplinary approach, regardless of the underlying cause. We hope that our findings are of use to readers in identifying possible aetiologies that should be considered in adult patients presenting with stridor.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
References
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